Voices on one staff handled like 2 parts in playback and mixer

Hi!

I am trying to teach my children in the children's choir to do some part singing. In stead of 2 systems I prefer writing down the score on one system. I color all the notes for group 1 blue, and I color all the notes for group 2 red. It is more clear for them to see how the two melodies are related to each other when it is all written on one staff.

But now my question or feature request.

How cool and handy would it be if I could mute one of the 'parts' (voices) during playback. So I can demonstrate to them (or they could do this at home) how voice 1 sounds, and how voice 2 sounds, and how they sound together. 

Perhaps I am the only person in the world who would like this feature, but I'd thought: let me ask this!